This invention relates to polymer systems reinforced with delaminated or exfoliated multi-layered silicates, that is, nanocomposite polymer systems.
Nanocomposite polymers are compositions comprising a relatively high number (but relatively low weight) of exfoliated multi-layered silicate material dispersed in a given volume of continuous polymer matrix, U.S. Pat. No. 5,717,000 to Seema V. Karande, Chai-Jing Chou, Jitka H. Solc and Kyung W. Suh, herein fully incorporated by reference. As discussed in the ""000 patent and as is well known in the art, nanocomposite polymers exhibit many increased physical property enhancements at a much lower volume percent of filler than conventionally filled polymers. For example, when nanocomposite polymers are formed into a film, the exfoliated multi-layered silicate material can be oriented in the direction parallel to the film surface, which contributes to the barrier properties of the film, U.S. Pat. No. 5,164,460, herein fully incorporated by reference.
The instant invention has twelve embodiments. The first embodiment is an improved process for making a structural foamed polymer comprising the steps of dispersing a gas-producing material into a fluid polymer at a first pressure followed by a second pressure less than the first pressure, the difference between the first pressure and the second pressure being sufficient to generate bubbles of gas in the fluid polymer. The improvement comprises the step of dispersing a multi-layered silicate material with the polymer so that the polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The second embodiment of the instant invention is an improved structural foamed polymer comprising gas cells having polymer walls. The improvement comprises the polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The third embodiment of the instant invention is an improved process for making a multilayer polymer film or sheet comprising the step of coextruding layers of at least two different polymers or at least two different layers of the same polymer to form the multilayer polymer film or sheet. The improvement comprises the step of dispersing a multilayered silicate material with at least one polymer so that the at least one polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The fourth embodiment of the instant invention is an improved multilayer polymer film, sheet or tube comprising layers of at least two different polymers or at least two layers of the same polymer. The improvement comprises at least one polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The fifth embodiment of the instant invention is an improved pultrusion process comprising the steps of impregnating a reinforcing fiber bundle with a polymer and forming a structural profile. The improvement comprises the step of dispersing a multilayered silicate material with the polymer so that the polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The sixth embodiment of the instant invention is an improved pultrusion structural profile comprising a reinforcing fiber bundle impregnated with a polymer. The improvement comprises the polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The seventh embodiment of the instant invention is an improved compression molding process comprising the step of compression molding an extruded fiber reinforced polymer pre-form. The improvement comprises the step of dispersing a multi-layered silicate material with the polymer so that the polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The eighth embodiment of the instant invention is an improved article, the article made by compression molding an extruded fiber reinforced polymer pre-form. The improvement comprises the polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The ninth embodiment of the instant invention is an improved process for making strand foamed polymer comprising the steps of extruding a polymer through a plurality of openings to form strands and then coalescing the strands. The improvement comprises the step of dispersing a multi-layered silicate material with the polymer so that the polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The tenth embodiment of the instant invention is improved strand foamed polymer article. The improvement comprises the polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
The eleventh embodiment of the instant invention is an improved SCORIM process for molding a polymer into an article comprising the step of introducing the polymer into a mold by reciprocating flow. The improvement comprises the step of dispersing a multi-layered silicate material with the polymer so that the polymer has dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate.
The twelfth embodiment of the instant invention is an improved SCORIM molded polymer article. The improvement comprises the polymer having dispersed therein single layers of silicate material, double layers of silicate material, triple layers of silicate material, four layers of silicate material, five layers of silicate material and more than five layers of silicate material, the volume percent of the one, two, three, four and five layers of silicate material being greater than the volume percent of the more than five layers of silicate material.
In each of the above embodiments an important benefit of the instant invention is the orientation of the plane of the layers of silicate material. More specifically, most of the layers of silicate material have substantially the same orientation (within thirty degrees of angle of the major surface of the fabricated material or of the interface of a multilayer structure) and this orientation improves the properties of the product. In the structural foamed polymer embodiment, the orientation is parallel to the cell wall with, for example, about seventy percent of the layers being within thirty degrees of parallel with the cell wall. In the multilayer polymer film, sheet or tube embodiment, the orientation is parallel to major surface of the film, sheet or tube. In the pultrusion embodiment, the orientation is parallel to fiber bundle. In the compression molding embodiment, the orientation is parallel to the reinforcing fibers. In the strand foamed polymer embodiment, the layers of silicate material are partially oriented by the initial extrusion process prior to foaming and further oriented parallel to the cell wall during foaming. In the SCORIM embodiment, the alignment is parallel to the plane of the part being molded. Another important benefit of the instant invention is that its articles can be relatively large (more than one kilogram) in comparison with articles made according to the prior art. The amount of multi-layered silicate material used in the instant invention is preferably between one and twenty weight percent.